This invention relates to apparatus for advancing or moving U-shaped metal clips on a guide rail into a clip attachment apparatus.
The use of U-shaped metal clips for closure of packages by attachment about gathered packaging material is disclosed in prior patents, for example, U.S. Pat. No. 4,766,713 which is incorporated herewith by reference. Typically, the U-shaped metal clips are supported on a guide rail which receives and supports a plurality of the clips and directs or guides them, one at a time, into a window of a clip channel. Each clip positioned in the channel is then driven by a punch about gathered material and against a die to thereby close or wrap the clip about the gathered material. Each clip is fed into the window by means of gravity, alone or assisted by means of a weight which is placed on the clips to facilitate gravity feeding. Alternatively, a friction wheel is engaged against the sides of the clips to force them into the window of the clip attachment apparatus.
The described clip advancement mechanisms have been successful and useful. However, when long coils of clips are to be fed along a rail and into a clipper, the use of gravity feed or a weight on top of the clips becomes an impractical method for feeding of the clips. Use of friction wheels, while generally satisfactory, does not necessarily provide the positive clip feeding action required. Thus, there is the a need to provide an improved clip advance mechanism.